This invention relates a method and system for forming unique micro discrete indicia on a gemstone such as a diamond using near-field optical imaging.
Recent advances in optics provide for a method of exposure of materials on a length scale much smaller than previously realized. Such near-field optical methods are realized by placing an aperture or a lens in close proximity to the surface of the sample or material to be exposed. Special methods for positioning control of the aperture or lens are required, as the distance between the optical elements (aperture or lens) is extremely small. Betzig and Trautman in U.S. Pat. No. 5,272,330 reported on the use of tapered optical fibers as a means of providing exposures in extremely small areas; exposures of the size of 10 nm in area are now relatively commonplace. In this case, the fiber tip position is maintained to be within some nanometers (typically 10-50) of the target surface. Others (see, for example, the review by Q. Wu, L. Ghislain, and V. B. Elings, Proc. IEEE (2000), 88(9), pg. 1491-1498) have developed means of exposure by the use of the solid immersion lens (SIL). Exposures produced by means of the SIL or other near-field optical methods can be much smaller in spatial extent than those produced by conventional optical systems and still be readable.
Optical means to mark diamonds and other gemstones have been previously described. Kaplan et al. in U.S. Pat. No. 6,211,484 B1 describe the use of a pulsed laser system and precision mechanical positioning controls to mark gemstones and a process to produce a secure certificate of authenticity. The laser in this instance operates with an approximate wavelength of 530 nanometers. This system achieves a positioning accuracy of about plus or minus a micron. The laser exposure produces a series of ablated or graphitic spots on the gemstone surface.
Smith et al. in U.S. Pat. No. 6,187,213 B1 describe the use of an ultraviolet (UV) laser system for marking diamond. The use of the 193 nanometers exposure with conventional optical elements produces a mark that is invisible because of its small size when viewed using an xc3x9710 loupe.
In U.S. Pat. No. 5,753,887, Rosenwasser et al. describe the use of a laser system for engraving indicia on gemstones. Their invention entails the use of a gemstone holding system that minimizes internal exposure and thus damage to the internal structure of the gemstone. This minimization is accomplished by use of light transmissive elements to hold and position the gemstone. Such minimization is especially important in the application of novelty marking of larger gemstones where some considerable optical exposure is required in order to mark the gemstone.
The prior art does not teach marking a gemstone using near-field optics. Such near-field technology is used in the present invention to provide a means of marking a gemstone with micro discrete indicia and to use these micro discrete indicia for the purpose of authentication and personalization. The size of the micro discrete indicia produced using near-field technology is such that they do detract from the physical appearance of the gemstone.
The prior art does not teach the forming of the micro discrete indicia on a gemstone using near-field optics to alter the color of gemstone materials.
The prior art also does not teach linking the micro discrete indicia produced using near-field optics to an owner, retailer, or producer via a database for the purpose of authentication.
In accordance with one aspect of the present invention there is provided a method for providing micro-discrete indicia on a gemstone, comprising the steps of:
providing a gemstone;
selecting an area on the gemstone for placement of a micro-discrete indicia; and
forming the micro-discrete indicia on the gemstone using near-field optics.
In accordance with another aspect of the present invention there is provided a method for reading a micro-discrete indicia on a gemstone, comprising the steps of:
locating the micro-discrete indicia on the gemstone; and
reading the micro-discrete indicia using near-field optics.
In accordance with yet another aspect of the present invention there is provided a gemstone having a micro-discrete indicia formed thereon wherein the micro-discrete indicia image was formed using near-field optics.